Integrated Fan-Out Structure and Method of Forming

ABSTRACT

Semiconductor devices and methods of forming are provided. A molding compound extends along sidewalls of a first die and a second die. A redistribution layer is formed over the first die, the second die, and the molding compound. The redistribution layer includes a conductor overlying a gap between the first die and the second die. The conductor is routed at a first angle over an edge of the first die. The first angle is measured with respect to a straight line that extends along a shortest between the first die and the second die, and the first angle is greater than 0.

PRIORITY CLAIM AND CROSS-REFERENCE

This is a divisional of U.S. patent application Ser. No. 14/942,627,filed on Nov. 16, 2015, entitled “Integrated Fan-Out Structure andMethod of Forming,” which application is incorporated herein byreference.

BACKGROUND

With the evolving of semiconductor technologies, semiconductorchips/dies are becoming increasingly smaller. In the meantime, morefunctions need to be integrated into the semiconductor dies.Accordingly, the semiconductor dies need to have increasingly greaternumbers of I/O pads packed into smaller areas, and the density of theI/O pads rises quickly over time. As a result, the packaging of thesemiconductor dies becomes more difficult, which adversely affects theyield of the packaging.

Conventional package technologies can be divided into two categories. Inthe first category, dies on a wafer are packaged before they are sawed.This packaging technology has some advantageous features, such as agreater throughput and a lower cost. Further, less underfill or moldingcompound is needed. However, this packaging technology also suffers fromdrawbacks. As aforementioned, the sizes of the dies are becomingincreasingly smaller, and the respective packages can only be fan-intype packages, in which the I/O pads of each die are limited to a regiondirectly over the surface of the respective die. With the limited areasof the dies, the number of the I/O pads is limited due to the limitationof the pitch of the I/O pads. If the pitch of the pads is to bedecreased, solder bridges may occur. Additionally, under the fixedball-size requirement, solder balls must have a certain size, which inturn limits the number of solder balls that can be packed on the surfaceof a die.

In the other category of packaging, dies are sawed from wafers beforethey are packaged, and only “known-good-dies” are packaged. Anadvantageous feature of this packaging technology is the possibility offorming fan-out packages, which means the I/O pads on a die can beredistributed to a greater area than the die, and hence the number ofI/O pads packed on the surfaces of the dies can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the embodiments, and the advantagesthereof, reference is now made to the following descriptions taken inconjunction with the accompanying drawings, in which:

FIGS. 1 through 16 are cross-sectional views of intermediate stages inthe manufacturing of a Through Via (TV) package in accordance with someexemplary embodiments;

FIGS. 17-19 illustrate cross-sectional and plan views of die-to-diemetal connections in accordance with exemplary embodiments; and

FIGS. 20 through 22 are cross-sectional views of intermediate stages inthe manufacturing of a TV package in accordance with some exemplaryembodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

An Integrated Fan-Out (“InFO”) package including and methods of formingthe same are provided in accordance with various exemplary embodiments.The intermediate stages of forming the InFO package are illustrated andvariations of embodiments are discussed.

FIGS. 1-16 illustrate cross-sectional views of intermediate steps informing a semiconductor package in accordance with some embodiments.Referring first to FIG. 1, there is shown a carrier substrate 20 havinga release layer 22 formed thereon. Generally, the carrier substrate 20provides temporary mechanical and structural support during subsequentprocessing steps. The carrier substrate 20 may include any suitablematerial, such as, for example, silicon based materials, such as asilicon wafer, glass or silicon oxide, or other materials, such asaluminum oxide, a ceramic material, combinations of any of thesematerials, or the like. In some embodiments, the carrier substrate 20 isplanar in order to accommodate further processing.

The release layer 22 is an optional layer formed over the carriersubstrate 20 that may allow easier removal of the carrier substrate 20.As explained in greater detail below, various layers and devices will beplaced over the carrier substrate 20, after which the carrier substrate20 may be removed. The optional release layer 22 aids in the removal ofthe carrier substrate 20, reducing damage to the structures formed overthe carrier substrate 20. The release layer 22 may be formed of apolymer-based material. In some embodiments, the release layer 22 is anepoxy-based thermal release material, which loses its adhesive propertywhen heated, such as a Light-to-Heat-Conversion (LTHC) release coating.In other embodiments, the release layer 22 may be an ultra-violet (UV)glue, which loses its adhesive property when exposed to UV light. Therelease layer 22 may be dispensed as a liquid and cured. In otherembodiments, the release layer 22 may be a laminate film laminated ontothe carrier substrate 20. Other release layers may be utilized.

Referring to FIG. 2, buffer layer 24 is formed over release layer 22.Buffer layer 24 is a dielectric layer, which may be a polymer (such aspolybenzoxazole (PBO), polyimide, benzocyclobutene (BCB), or the like),a nitride (such as silicon nitride or the like), an oxide (such assilicon oxide, PhosphoSilicate Glass (PSG), BoroSilicate Glass (BSG),Boron-doped PhosphoSilicate Glass (BPSG), or a combination thereof, orthe like), or the like, and may be formed, for example, by spin coating,lamination, Chemical Vapor Deposition (CVD), or the like. In someembodiments, buffer layer 24 is a planar layer having a uniformthickness, wherein the thickness may be between about 2 μm and about 6μm. The top and the bottom surfaces of buffer layer 24 are also planar.

Referring now to FIGS. 2 to 6, there is shown formation of through vias(“TVs”) 33 (see FIG. 6) in accordance with some embodiments. The throughvias 33 provide an electrical connection from one side of the package toanother side of the package. For example, as will be explained ingreater detail below, one or more dies will be mounted to the bufferlayer 24 and a molding compound will be formed around the through viasand the die. Subsequently, another device, such as another die, package,substrate, or the like, may be attached to the die and the moldingcompound. The through vias 33 provide an electrical connection betweenthe another device and the backside of the package without having topass electrical signals through the die mounted to the buffer layer 24.

The through vias 33 may be formed, for example, by forming a conductiveseed layer 26 over the buffer layer 24, as shown in FIG. 2. In someembodiments, seed layer 26 is a metal layer, which may be a single layeror a composite layer comprising a plurality of sub-layers formed ofdifferent materials. Seed layer 26 may be made of copper, titanium,nickel, gold, or a combination thereof, or the like. In someembodiments, seed layer 26 comprises a titanium layer and a copper layerover the titanium layer. Seed layer 26 may be formed using, for example,physical vapor deposition (PVD), CVD, atomic layer deposition (ALD), acombination thereof, or the like. In some embodiments, seed layer 26comprises titanium layer 26A and copper layer 26B over titanium layer26A. In alternative embodiments, seed layer 26 is a copper layer.

Turning to FIG. 3, a mask layer, such as patterned photoresist layer 28,may be deposited and patterned, wherein openings 30 in the mask layerexpose the seed layer 26. Referring to FIG. 4, openings 30 (see FIG. 2)may be filled with a conductive material using, for example, anelectroless plating process or an electrochemical plating process,thereby creating metal features 32. The plating process mayuni-directionally fill openings (e.g., from seed layer 26 upwards) inthe patterned photoresist layer 28. Uni-directional filling may allowfor more uniform filling of such openings. Alternatively, another seedlayer may be formed on sidewalls of openings 30 in the patternedphotoresist layer 28, and such openings may be filledmulti-directionally. Metal features 32 may comprise copper, aluminum,tungsten, nickel, solder, or alloys thereof. The top-view shapes ofmetal features 32 may be rectangles, squares, circles, or the like. Theheights of metal features 32 are determined by the thickness of thesubsequently placed dies 34 (shown in FIG. 7), with the heights of metalfeatures 32 greater than the thickness of dies 34 in some embodiments.

Next, the mask layer may be removed, for example in an ashing and/or wetstrip process, as shown in FIG. 5. Referring to FIG. 6, an etch step isperformed to remove the exposed portions of seed layer 26, wherein theetching may be an anisotropic etching. The portions of seed layer 26that are overlapped by metal features 32, on the other hand, remain notetched. Metal features 32 and the remaining underlying portions of seedlayer 26 form through vias 33. Although seed layer 26 is shown as alayer separate from metal features 32, when seed layer 26 is formed of amaterial similar to or the same as the respective overlying metalfeatures 32, seed layer 26 may be merged with metal features 32 with nodistinguishable interface between. In some embodiments, there existdistinguishable interfaces between seed layer 26 and the overlying metalfeatures 32. The through vias 33 can also be realized with metal wirestuds placed by a wire bonding process, such as a copper wire bondingprocess. The use of a wire bonding process may eliminate the need fordepositing seed layer 26, depositing and patterning mask layer 28, andplating to form the through vias 33.

FIG. 7 illustrates attaching an integrated circuit die 34 to thebackside of buffer layer 24 in accordance with some embodiments. In someembodiments, the integrated circuit die 34 may be adhered to bufferlayer 24 by an adhesive layer 36, such as a die-attach film (DAF). Athickness of the adhesive layer 36 may be in a range from about 5 μm toabout 50 μm, such as about 10 um. The integrated circuit die 34 may betwo dies as illustrated in FIG. 7, or in some embodiments, one, or morethan two dies, may be attached, and may include any die suitable for aparticular approach. For example, the integrated circuit dies 34 mayinclude a static random access memory (SRAM) chip or a dynamic randomaccess memory (DRAM) chip, a processor, a memory chip, logic chip,analog chip, digital chip, a central processing unit (CPU), a graphicsprocessing unit (GPU), or a combination thereof, or the like. Theintegrated circuit dies 34 may be attached to any suitable location fora particular design or application.

Before being attached to the buffer layer 24, each integrated circuitdie 34 may be processed according to applicable manufacturing processesto form integrated circuits (not shown) in the integrated circuit die34. In some exemplary embodiments, the integrated circuit dies 34include metal pillars 40 (such as copper posts) that are electricallycoupled to devices such as transistors (not shown) in dies 34. In someembodiments, dielectric layer 38 is formed at the top surface of therespective die 34, with metal pillars 40 disposed in dielectric layer38. The top surfaces of metal pillars 40 may be level with the topsurfaces of dielectric layer 38 in some embodiments. In someembodiments, before integrated circuit dies 34 are attached to bufferlayer 24, dielectric layer 38 may be patterned so that an edge of thedielectric layer 38 is offset a distance A from a lower edge of theintegrated circuit die 34, where distance A is measured in a plan view,as shown in FIG. 7. In some embodiments, distance A is about 5 μm toabout 100 μm, such as about 30 μm. As will be explained in greaterdetail below, in some embodiments this offset may enable die-to-diemetal connections with greater reliability during thermal cycling. Anysuitable method of forming the offset may be used. In some embodiments,dielectric layer 38 is photosensitive, and the offset may be formed byexposing and developing. In some embodiments, the offset may be formedusing an etching process.

Referring to FIG. 8, molding material 42 is molded on dies 34 and TVs33. Molding material 42 fills the gaps between dies 34 and TVs 33, andmay be in contact with buffer layer 24. Furthermore, molding material 42is filled into the gaps between metal pillars 40 when metal pillars 40are protruding metal pillars. Molding material 42 may include a moldingcompound, a molding underfill, an epoxy, or a resin. The top surface ofmolding material 42 is higher than the top ends of metal pillars 40 andTVs 33.

Next, a grinding step is performed to thin molding material 42, untilmetal pillars 40 and TVs 33 are exposed. The resulting structure isshown in FIG. 9. Due to the grinding, the top ends of metal features 32are substantially level (coplanar) with the top ends of metal pillars40, and are substantially level (coplanar) with the top surface ofmolding material 42. As a result of the grinding, metal residues such asmetal particles may be generated, and left on the top surfaces.Accordingly, after the grinding, a cleaning may be performed, forexample, through a wet etching, so that the metal residue is removed.

Next, referring to FIGS. 10-16, one or more redistribution layers (RDLs)are formed. Generally, RDLs provide a conductive pattern that allows apin-out contact pattern for a completed package different than thepattern of through vias 33 and/or metal pillars 40, allowing for greaterflexibility in the placement of through vias 33 and dies 34. The RDLsmay be utilized to provide an external electrical connection to dies 34and/or to through vias 33. The RDLs may further be used to electricallycouple dies 34 to through vias 33, which may be electrically coupled toone or more other packages, package substrates, components, the like, ora combination thereof. The RDLs comprise conductive lines and viaconnections, wherein via connections connect an overlying line to anunderlying conductive feature.

The RDLs may be formed using any suitable process. For example, as shownin FIG. 10, in some embodiments, dielectric layer 50 is formed on themolding material 42 and integrated circuit die 34. In some embodiments,dielectric layer 50 is formed of a polymer, which may be aphoto-sensitive material such as polybenzoxazole (PBO), polyimide,benzocyclobutene (BCB), or the like, that may be patterned usinglithography. In other embodiments, dielectric layer 50 is formed of anitride such as silicon nitride, an oxide such as silicon oxide,PhosphoSilicate Glass (PSG), BoroSilicate Glass (BSG), Boron-dopedPhosphoSilicate Glass (BPSG), or the like. Dielectric layer 50 may beformed by spin coating, lamination, CVD, the like, or a combinationthereof.

Referring to FIG. 11, dielectric layer 50 is then patterned to formopenings to expose metal pillars 40 and the through vias 33. Inembodiments in which dielectric layer 50 is formed of a photo-sensitivematerial, the patterning may be performed by exposing dielectric layer50 in accordance with a desired pattern and developed to remove theunwanted material, thereby exposing metal pillars 40 and the throughvias 33. Other methods, such as using a patterned mask and etching, mayalso be used to pattern dielectric layer 50.

Referring to FIG. 12, a seed layer 51 is formed over dielectric layer 50and in the openings formed in dielectric layer 50. In some embodiments,seed layer 51 is a metal layer, which may be a single layer or acomposite layer comprising a plurality of sub-layers formed of differentmaterials. In some embodiments, seed layer 51 comprises a titanium layerand a copper layer over the titanium layer. Seed layer 51 may be formedusing, for example, PVD, or the like.

Referring to FIG. 13, a mask 55 is then formed and patterned on seedlayer 51 in accordance with a desired redistribution pattern, such asthe pattern illustrated in FIG. 13. In some embodiments, the mask 55 isa photoresist formed by spin coating or the like and exposed to lightfor patterning. The patterning forms openings through the mask 55 toexpose seed layer 51.

Next, referring to FIG. 14, a conductive material is formed in theopenings of the mask and on the exposed portions of seed layer 51. Theconductive material may be formed by plating, such as electroplating orelectroless plating, or the like. The conductive material may comprise ametal, like copper, titanium, tungsten, aluminum, or the like. Then,referring to FIG. 15, the mask and portions of seed layer 51 on whichthe conductive material is not formed, are removed. The photoresist maybe removed by an acceptable ashing or stripping process, such as usingan oxygen plasma or the like. Once the photoresist is removed, exposedportions of the seed layer are removed, such as by using an acceptableetching process, such as by wet or dry etching.

Referring to FIG. 16, dielectric layer 52 is formed over dielectriclayer 50 to provide a more planar surface for subsequent layers and maybe formed using similar materials and processes as used to formdielectric layer 50. In some embodiments, dielectric layer 52 is formedof polymer, a nitride, an oxide, or the like. In some embodiments,dielectric layer 52 is PBO formed by a spin-on process. Together,dielectric layers 50 and 52, and the conductive lines and viaconnections disposed within these layers, form one redistribution layer53.

In some embodiments, there may exist coefficient of thermal expansion(CTE) mismatch between the material typically used for the integratedcircuit dies 34 and the material used for RDL 53 dielectric layers, suchas dielectric layers 50 and 52. The CTE mismatch between these materialsmay lead to reduced reliability of die-to-die metal connections,particularly during thermal cycling. For example, the different rates ofexpansion and contraction during changing temperatures between theintegrated circuit dies 34 and the metal connections within RDL 53,caused by the CTE mismatch, creates stress on the metal connectionswithin RDL 53. The stress is particularly an issue for metal connectionsoverlying a gap between two integrated circuit dies 34. In someembodiments, increasing the length of the metal connections of RDL 53between the integrated circuit dies 34 may help to reduce stress on themetal connections and to increase reliability of the package,particularly during thermal cycling.

Referring to FIGS. 17-19, cross-sectional and plan views of die-to-diemetal connections 57 are shown in accordance with different embodiments.The cross sectional views of FIGS. 17-19 are depicted along the metalconnection 57 over the gap between the two integrated circuit dies 34,as shown by the x-x′ line in the plan views of each of FIGS. 17-19. Ineach depicted package, the length of the metal connection 57 over thegap between two integrated circuit dies 34 is increased, which mayreduce stress on the metal connection 57 and increase reliability of theconnection 57 during thermal cycling.

Referring to FIG. 17, in some embodiments a die-to-die metal connection57 forms an angular line over the gap between two integrated circuitdies 34. FIG. 17 depicts both a cross-sectional view of the package anda plan view of the die-to-die metal connection 57, with thecross-sectional view extending along the die-to-die metal connection 57shown in the x-x′ line in the plan view. Compared to a straight lineextending directly between two integrated circuit dies 34 along theshortest distance between the two lines, the angular line depicted inFIG. 17 is longer, which may help to reduce stress on the metalconnection 57 during thermal cycling. In some embodiments, the angularline may help to increase reliability of the connection 57.

In some embodiments, the angular line forms an angle θ with respect to aline that extends in a straight line along the shortest distance betweenone of the integrated circuits 34 to the other integrated circuit die34. Angle θ is greater than 0 in some embodiments. In some embodiments,the angle θ is greater than about 15 degrees, and in some embodimentsangle θ may be about 45 degrees. In some embodiments, angle θ is lessthan about 90 degrees. In some embodiments, the angular line is routedover the edge of each integrated circuit die 34 in a manner that it isnon-perpendicular to the edge of the integrated circuit die 34. In someembodiments, compared to a normalized stress level of 1 when thedie-to-die metal connection is routed along a straight line extendingalong the shortest distance from one integrated circuit die 34 to theother integrated circuit die 34 (when the angle θ is 0 degrees), to whenthe angular line is routed along an angle θ of about 22.5 degrees, thestress level may be reduced to about 0.89. In some embodiments, an angleθ of about 45 degrees may reduce the stress level to about 0.65.

In some embodiments, the metal connection 57 comprises a first turningpoint, which is located over a first integrated circuit die 34 where themetal connection 57 is first routed at angle θ. The first turning pointis located least a distance B from the interface of dielectric layer 38of the first integrated circuit 34 and molding material 42, wheredistance B is measured in a plan view. In some embodiments, distance Bmay be greater than 10 μm, such as about 30 μm. As described above, theinterface of the dielectric layer 38 and molding material are offsetfrom a lower edge of integrated circuit die 34 by a distance A, wheredistance A is measured in a plan view. In some embodiments, distance Amay be about 5 μm to about 100 μm, such as about 30 μm. The metalconnection 57 also comprises a second turning point over the secondintegrated circuit 34, where the metal connection 57 first routes awayfrom angle θ and back to a straight line, or whatever the desiredrouting may be. The second turning point is located at least a distanceB from the interface of the dielectric layer 38 of the second integratedcircuit 34 and the molding material 42, where B is measured in a planview. In some embodiments, distance B may be greater than 10 μm, such asabout 30 μm. For the second integrated circuit, as with the firstintegrated circuit, the interface of the dielectric layer 38 and moldingmaterial 42 are offset from a lower edge of integrated circuit die 34 bya distance A. In some embodiments, distance A may be about 5 μm to about100 μm, such as about 30 μm.

Other embodiments are possible. FIG. 18 depicts a package in which adie-to-die metal connection 57 is a multi-segment angular line. FIG. 18depicts both a cross-sectional view of the package and a plan view ofthe die-to-die metal connection 57, with the cross-sectional viewextending along the die-to-die metal connection 57 shown in x-x′ line inthe plan view. Compared to a straight line extending along a shortestdistance between two integrated circuit dies 34, the multi-segmentangular line depicted in FIG. 18 is longer, which may help to reducestress on the metal connection 57 during thermal cycling. In someembodiments, the multi-segment angular line may help to increasereliability of the connection 57.

In some embodiments, the multi-segment angular line comprises a firstangular segment, a straight segment, and a second angular segment. Insome embodiments, the first angular segment partially overlies the firstdie and forms an angle θ₁ with respect to a line that extends in astraight line along the shortest distance from one of the integratedcircuits 34 to the other. In some embodiments, angle θ₁ is greater that0. In some embodiments, the angle θ₁ is greater than about 15 degrees,and in some embodiments may be about 45 degrees. In some embodiments,angle θ₁ is less than about 90 degrees. In some embodiments, the secondangular segment partially overlies the second integrated circuit 34 andforms an angle θ₂ with respect to a line that extends in a straight linealong the shortest distance from one of the integrated circuits 34 toanother. In some embodiments, angle θ₂ is greater than 0. In someembodiments, the angle θ₂ is greater than about 15 degrees, and in someembodiments may be about 45 degrees. In some embodiments, angle θ₂ isless than about 90 degrees. The first angular segment and the secondangular segment are connected by the straight segment. In someembodiments, when the gap between two integrated circuit dies is about25 μm, the straight segment may be greater than 5 μm, such as about 12μm.

In some embodiments, the metal connection 57 comprises a first turningpoint, which is located over a first integrated circuit die 34 where themetal connection 57 is first routed at angle θ. The first turning pointis located least a distance B from the interface of dielectric layer 38of the first integrated circuit die 34 and molding material 42, wheredistance B is measured in a plan view. In some embodiments, distance Bmay be greater than 10 μm, such as about 30 μm. As described above, theinterface of the dielectric layer 38 and molding material are offsetfrom a lower edge of the first integrated circuit die 34 by a distanceA, where distance A is measured in a plan view. In some embodiments,distance A may be about 5 μm to about 100 μm, such as about 30 μm. Themetal connection 57 also comprises a second turning point over thesecond integrated circuit 34, where the metal connection 57 first routesaway from angle θ and back to a straight line, or whatever the desiredrouting is. The second turning point is located at least a distance Bfrom the interface of the dielectric layer 38 of the second integratedcircuit die 34 and the molding material 42, where B is measured in aplan view. In some embodiments, distance B may be greater than 10 μm,such as about 30 μm. For the second integrated circuit, as with thefirst integrated circuit, the interface of the dielectric layer 38 andmolding material 42 are offset from a lower edge of integrated circuitdie 34 by a distance A. In some embodiments, distance A may be about 5μm to about 100 μm, such as about 30 μm.

FIG. 19 depicts a package in which a die-to-die metal connection 57forms a two segment line over a gap between two integrated circuit dies34. FIG. 19 depicts both a cross-sectional view of the package and aplan view of the die-to-die metal connection 57, with thecross-sectional segment extending along the die-to-die metal connection57 depicted in x-x′ line in the plan view. In some embodiments, thefirst segment is routed at an acute angle, θ₁, with respect to an edgeof an integrated circuit die 34 that faces a second integrated circuitdie 34. In some embodiments, angle θ₁ is less than about 90 degrees. Thesecond segment may be connected to the first segment and routed at anacute angle θ₂, with respect to an edge of the second integrated circuitdie that faces the first integrated circuit. In FIG. 19, the twosegments form a right angle to each other, but other embodiments arepossible. In some embodiments, an angle that is greater than 90 degreesmay be used. Compared to a straight line extending along a shortestdistance between two integrated circuit dies 34, the two segment linedepicted in FIG. 19 is longer, which may help to reduce stress on themetal connection during thermal cycling. In some embodiments, the twosegment line may help to increase reliability of the connection 57.

In some embodiments, the metal connection 57 comprises a first turningpoint, which is located over a first integrated circuit die 34 where themetal connection is first routed at angle θ. The first turning point islocated least a distance B from the interface of dielectric layer 38 ofthe first integrated circuit die 34 and molding material 42, wheredistance B is measured in a plan view. In some embodiments, distance Bmay be greater than 10 μm, such as about 30 μm. As described above, theinterface of the dielectric layer 38 of the first integrated circuit die34 and molding material are offset from a lower edge of the firstintegrated circuit die 34 by a distance A, where distance A is measuredin a plan view. In some embodiments, distance A may be about 5 μm toabout 100 μm, such as about 30 μm. The metal connection 57 alsocomprises a second turning point over the second integrated circuit 34,where the metal connection 57 first routes away from angle θ and back toa straight line, or whatever the desired routing may be. The secondturning point is located at least a distance B from the interface of thedielectric layer 38 of the second integrated circuit 34 and the moldingmaterial 42, where B is measured in a plan view. In some embodiments,distance B may be greater than 10 μm, such as about 30 μm. For thesecond integrated circuit 34, as with the first integrated circuit 34,the interface of the dielectric layer 38 and molding material 42 areoffset from a lower edge of integrated circuit die 34 by a distance A.In some embodiments, distance A may be about 5 μm to about 100 μm, suchas about 30 μm.

Although one layer of RDLs 53 is depicted in FIGS. 17-20, in someembodiments, additional RDLs 53 may be formed. The additional RDLs maybe formed using similar processes and materials as described above withreference to other RDLs.

FIG. 20 illustrates an under bump metallization (UBM) 70 formed andpatterned over an uppermost metallization pattern in accordance withsome embodiments, thereby forming an electrical connection with anuppermost metallization layer. The UBM 70 provides an electricalconnection upon which an electrical connector, e.g., a solder ball/bump,a conductive pillar, or the like, may be placed. In an embodiment, theunder bump metallization 70 includes a diffusion barrier layer, a seedlayer, or a combination thereof. The diffusion barrier layer may includeTi, TiN, Ta, TaN, or combinations thereof. The seed layer may includecopper or copper alloys. However, other metals, such as nickel,palladium, silver, gold, aluminum, combinations thereof, andmulti-layers thereof, may also be included. In an embodiment, under bumpmetallization 70 is formed using sputtering. In other embodiments,electro plating may be used.

Connectors 68 are formed over the under bump metallization 70 inaccordance with some embodiments. The connectors 68 may be solder balls,metal pillars, controlled collapse chip connection (C4) bumps, microbumps, electroless nickel-electroless palladium-immersion gold technique(ENEPIG) formed bumps, combination thereof (e.g., a metal pillar havinga solder ball attached thereof), or the like. The connectors 68 mayinclude a conductive material such as solder, copper, aluminum, gold,nickel, silver, palladium, tin, the like, or a combination thereof. Insome embodiments, the connectors 68 comprise a eutectic material and maycomprise a solder bump or a solder ball, as examples. The soldermaterial may be, for example, lead-based and lead-free solders, such asPb—Sn compositions for lead-based solder; lead-free solders includingInSb; tin, silver, and copper (SAC) compositions; and other eutecticmaterials that have a common melting point and form conductive solderconnections in electrical applications. For lead-free solder, SACsolders of varying compositions may be used, such as SAC 105 (Sn 98.5%,Ag 1.0%, Cu 0.5%), SAC 305, and SAC 405, as examples. Lead-freeconnectors such as solder balls may be formed from SnCu compounds aswell, without the use of silver (Ag). Alternatively, lead-free solderconnectors may include tin and silver, Sn—Ag, without the use of copper.The connectors 68 may form a grid, such as a ball grid array (BGA). Insome embodiments, a reflow process may be performed, giving theconnectors 68 a shape of a partial sphere in some embodiments.Alternatively, the connectors 68 may comprise other shapes. Theconnectors 68 may also comprise non-spherical conductive connectors, forexample.

In some embodiments, the connectors 68 comprise metal pillars (such as acopper pillar) formed by a sputtering, printing, electro plating,electroless plating, CVD, or the like, with or without a solder materialthereon. The metal pillars may be solder free and have substantiallyvertical sidewalls or tapered sidewalls.

Next, carrier substrate 20 is de-bonded from the package. Release layer22 is also cleaned from the package. The resulting structure is shown inFIG. 21. If more than one package has been formed on a wafer, the waferis singulated to form individual packages.

FIG. 22 illustrates the bonding of top package 76 to TV package 74,wherein the bonding may be through solder regions 68. In someembodiments, top package 76 includes dies 80 bonded to package substrate82. Dies 80 may include a memory die(s), which may be, for example, aStatic Random Access Memory (SRAM) die, a Dynamic Random Access Memory(DRAM) die, or the like.

In some embodiments, a method of forming a semiconductor device isprovided. The method includes forming a molding compound extending alongsidewalls of a first die and a second die. A redistribution layer isformed over the first die, the second die, and the molding compound, theredistribution layer including a conductor overlying a gap between thefirst die and the second die. The conductor is routed at a first angleover an edge of the first die. The first angle is measured with respectto a shortest line between the first die and the second die, and thefirst angle is greater than 0.

In some embodiments, a method of forming a semiconductor device isprovided. The method includes placing a first die on a substrate, a topsurface of the first die including a first dielectric layer. An edge ofthe first dielectric layer is offset from a lower edge of the first die.A second die is placed on the substrate, a top surface of the second dieincluding a second dielectric layer. An edge of the second dielectriclayer is offset from a lower edge of the second die. Molding compound isformed, extending along sidewalls of the first die and the second die. Athrough via extending through the molding compound is formed. Aredistribution layer is formed over the first die and the second die,the redistribution layer including a conductor overlying a gap betweenthe first die and the second die. The conductor is routed over the edgeof the first die in a manner that is non-perpendicular to an edge of thefirst die that faces the second die.

In some embodiments, a semiconductor device is provided. Thesemiconductor device includes a first die and a second die. Moldingmaterial extends between the first die and the second die. Aredistribution layer overlies the first die and the second die, theredistribution layer including a conductor overlying a gap between thefirst die and the second die. The conductor is routed at a first angleover an edge of the first die. The first angle is measured with respectto a shortest line between the first die and the second die, and thefirst angle is greater than 0.

A semiconductor device is provided in accordance with some embodiments.The semiconductor device includes a first die, a second die, and amolding material extending between the first die and the second die. Thesemiconductor device includes a redistribution layer overlying the firstdie and the second die, the redistribution layer including a conductorcontinuously extending, in a plan view, from a sidewall of the first diethat is closest to the second die to a sidewall of the second die thatis closest to the first die, the conductor being routed at a first angleover an edge of the first die, the first angle being measured in a planview and with respect to a shortest line between the first die and thesecond die, and the first angle being greater than 0. In an embodimentthe first die comprises a first dielectric layer on a first substrate,an edge of the first dielectric layer being offset from an edge of thefirst substrate, and the second die comprises a second dielectric layeron a top surface of a second substrate, an edge of the second dielectriclayer being offset from an edge of the second substrate, where theconductor comprises a first turning point over the first dielectriclayer, the first turning point being located where the conductor isfirst routed at the first angle. In an embodiment the conductor isrouted at the first angle over the edge of the second dielectric layer,and the first angle is greater than about 15 degrees. In an embodiment,the conductor comprises a second turning point over the seconddielectric layer, and the second turning point located where theconductor is first routed away from the first angle. In an embodiment,the conductor comprises: a first segment partially overlying over thefirst die and routed at the first angle, a second segment connected tothe first segment routed at a second angle, and a third segmentconnected to the second segment, partially overlying the second die, androuted at a third angle, the third angle being greater than 0, where thesecond angle and the third angle are measured in a plan view and withrespect to a shortest line between the first die and the second die. Inan embodiment, the conductor comprises a first segment partiallyoverlying the first die and routed at the first angle, and a secondsegment connected to the first segment, partially overlying the seconddie, and routed at a second angle, where the first segment is routed atan acute angle with respect to an edge of the first die that faces thesecond die, and the second angle is an acute angle with respect to anedge of the second die that faces the first die. In an embodiment thefirst segment forms a perpendicular angle to the second segment, theperpendicular angle being located over the molding material that extendsbetween the first die and the second die. In an embodiment the firstangle is about 45 degrees.

A semiconductor device is provided in accordance with some embodiments.The semiconductor device includes a first die and a second diepositioned next to the first die. The semiconductor device also includesa first dielectric layer overlying the first die and the second die. Thesemiconductor device also includes a conductor extending in the firstdielectric layer, where the conductor is continuous, in a plan view,between a sidewall of the first die and a sidewall of the second die,and where the conductor is routed at a first angle over an edge of thefirst die, the first angle being measured in the plan view with respectto the sidewall of the first die, and the first angle beingnon-perpendicular. In an embodiment the conductor extends in a straightline between the first die and the second die. In an embodiment theconductor is first routed to the first angle at a first turning point,the first turning point being located over the first die and offset fromthe sidewall of the first die. In an embodiment the conductor is routedat a second angle over an edge of the second die, the second angle beingmeasured in a plan view with respect to the sidewall of the second die,and the second angle being non-perpendicular. In an embodiment theconductor is first routed away from the second angle at a second turningpoint, the second turning point being located over the second die andoffset from the sidewall of the second die. In an embodiment theconductor is first routed away from the first angle at a third turningpoint, the third turning point being located over a line that extendsalong a shortest distance between the sidewall of the first die and thesidewall of the second die.

A semiconductor device is provided in accordance with some embodiments.The semiconductor device includes a first die, the first die comprisinga first substrate and a first dielectric layer overlying the firstsubstrate, an edge of the first substrate being offset from an edge ofthe first dielectric layer. The semiconductor device also includes asecond die positioned next to the first die, the second die comprising asecond substrate and a second dielectric layer overlying the secondsubstrate, an edge of the second substrate being offset from an edge ofthe second dielectric layer; The semiconductor device also includes aredistribution layer overlying the first die and the second die, theredistribution layer comprising a conductor that continuously extends,in a plan view, between a sidewall of the first die and a sidewall ofthe second die, where the conductor is routed across the sidewall of thefirst die at a first angle, where the first angle is measured in theplan view and with respect to a shortest line between the first die andthe second die, and the first angle being greater than 0. In anembodiment the conductor is first routed to the first angle at a firstturning point, the first turning point being located over the firstdielectric layer. In an embodiment the semiconductor device alsoincludes molding material extending between the first die and the seconddie, wherein the first turning point is laterally offset from aninterface between the molding material and the first dielectric layer.In an embodiment the conductor is routed across the sidewall of thesecond die at a second angle, wherein the first angle and the secondangle are the same. In an embodiment the conductor is first routed tothe second angle at a second turning point, the second turning pointbeing located over the second dielectric layer. In an embodiment thesemiconductor device also includes a molding material extending betweenthe first die and the second die, wherein the second turning point islaterally offset from an interface of the molding material and thesecond dielectric layer.

Although the embodiments and their advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the embodiments as defined by the appended claims. Moreover,the scope of the present application is not intended to be limited tothe particular embodiments of the process, machine, manufacture, andcomposition of matter, means, methods and steps described in thespecification. As one of ordinary skill in the art will readilyappreciate from the disclosure, processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed, that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein may be utilized according to the disclosure.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps. In addition, each claim constitutes a separateembodiment, and the combination of various claims and embodiments arewithin the scope of the disclosure.

1. A device, comprising: a first die; a second die; a molding material extending between the first die and the second die; and a redistribution layer overlying the first die and the second die, the redistribution layer including a conductor continuously extending, in a plan view, from a sidewall of the first die that is closest to the second die to a sidewall of the second die that is closest to the first die, the conductor being routed at a first angle over an edge of the first die, the first angle being measured in a plan view and with respect to a shortest line between the first die and the second die, and the first angle being greater than
 0. 2. The device according to claim 1, wherein: the first die comprises a first dielectric layer on a first substrate, an edge of the first dielectric layer being offset from an edge of the first substrate; and the second die comprises a second dielectric layer on a top surface of a second substrate, an edge of the second dielectric layer being offset from an edge of the second substrate; wherein the conductor comprises a first turning point over the first dielectric layer, the first turning point being located where the conductor is first routed at the first angle.
 3. The device according to claim 2, wherein the conductor is routed at the first angle over the edge of the second dielectric layer, and the first angle is greater than about 15 degrees.
 4. The device according to claim 3, wherein the conductor comprises a second turning point over the second dielectric layer, the second turning point located where the conductor is first routed away from the first angle.
 5. The device according to claim 1, wherein the conductor comprises: a first segment partially overlying over the first die and routed at the first angle; a second segment connected to the first segment routed at a second angle; and a third segment connected to the second segment, partially overlying the second die, and routed at a third angle, the third angle being greater than 0; wherein the second angle and the third angle are measured in a plan view and with respect to a shortest line between the first die and the second die.
 6. The device according to claim 1, wherein the conductor comprises: a first segment partially overlying the first die and routed at the first angle; and a second segment connected to the first segment, partially overlying the second die, and routed at a second angle; wherein the first segment is routed at an acute angle with respect to an edge of the first die that faces the second die, and the second angle is an acute angle with respect to an edge of the second die that faces the first die.
 7. The device according to claim 6, wherein the first segment forms a perpendicular angle to the second segment, the perpendicular angle being located over the molding material that extends between the first die and the second die.
 8. The device according to claim 1, wherein the first angle is about 45 degrees.
 9. A device, comprising: a first die; a second die positioned next to the first die; a first dielectric layer overlying the first die and the second die; a conductor extending in the first dielectric layer, wherein the conductor is continuous, in a plan view, between a sidewall of the first die and a sidewall of the second die, and wherein the conductor is routed at a first angle over an edge of the first die, the first angle being measured in the plan view with respect to the sidewall of the first die, and the first angle being non-perpendicular.
 10. The device according to claim 9, wherein the conductor extends in a straight line between the first die and the second die.
 11. The device according to claim 9, wherein the conductor is first routed to the first angle at a first turning point, the first turning point being located over the first die and offset from the sidewall of the first die.
 12. The device according to claim 9, wherein the conductor is routed at a second angle over an edge of the second die, the second angle being measured in a plan view with respect to the sidewall of the second die, and the second angle being non-perpendicular.
 13. The device according to claim 12, wherein the conductor is first routed away from the second angle at a second turning point, the second turning point being located over the second die and offset from the sidewall of the second die.
 14. The device according to claim 13, wherein the conductor is first routed away from the first angle at a third turning point, the third turning point being located over a line that extends along a shortest distance between the sidewall of the first die and the sidewall of the second die.
 15. A device, comprising: a first die, the first die comprising a first substrate and a first dielectric layer overlying the first substrate, an edge of the first substrate being offset from an edge of the first dielectric layer; a second die positioned next to the first die, the second die comprising a second substrate and a second dielectric layer overlying the second substrate, an edge of the second substrate being offset from an edge of the second dielectric layer; a redistribution layer overlying the first die and the second die, the redistribution layer comprising a conductor that continuously extends, in a plan view, between a sidewall of the first die and a sidewall of the second die, wherein the conductor is routed across the sidewall of the first die at a first angle, wherein the first angle is measured in the plan view and with respect to a shortest line between the first die and the second die, and the first angle being greater than
 0. 16. The device according to claim 15, wherein the conductor is first routed to the first angle at a first turning point, the first turning point being located over the first dielectric layer.
 17. The device according to claim 16, further comprising molding material extending between the first die and the second die, wherein the first turning point is laterally offset from an interface between the molding material and the first dielectric layer.
 18. The device according to claim 15, wherein the conductor is routed across the sidewall of the second die at a second angle, wherein the first angle and the second angle are the same.
 19. The device according to claim 18, wherein the conductor is first routed to the second angle at a second turning point, the second turning point being located over the second dielectric layer.
 20. The device according to claim 19, further comprising: a molding material extending between the first die and the second die, wherein the second turning point is laterally offset from an interface of the molding material and the second dielectric layer. 